Since women's ice hockey became an Olympic sport in Nagano in 1998, the two North American countries have dominated the podium — winning every gold medal and all but one of the silvers. The lack of competition, especially in preliminary round games, led IOC President Jacques Rogge to warn the sport's governing body after Vancouver, "We cannot continue without improvement."

Four years later, the chance of a Russian awakening on their home ice could be the biggest surprise of the Olympic tournament. And the format has been tweaked to add excitement and eliminate the blowouts that characterized so many of the round-robin games. (It also guarantees North American TV a matchup between the longtime rivals on Feb. 12).

"We of course know that progress takes time, and that the U.S. and Canada have top-quality programs," said Adam Steiss, a spokesman for the International Ice Hockey Federation. "But we certainly hope to see many competitive games in Sochi."

Here are five things to look for at the hockey puck-shaped Shayba Arena and at the Bolshoy Ice Dome, where the women's hockey medal round will be held:

NEW FORMAT: The old tournament split the eight countries into two equal groups based on their international rankings. That preserved the possibility that the U.S. and Canada wouldn't meet until the gold medal game, but it also led to them beating other teams by scores like 18-0 and 13-0 in the opening round.

Now, the top four teams in the world rankings are in one group, with the next four in the other. The top two teams in Group A will advance directly to the semifinals; the bottom two will play the top two Group B teams in the quarterfinals. If form holds, the United States and Canada would meet twice — the second in the gold medal game on Feb. 20 — and those 18-0 victories over Slovakia won't happen at all.

The format was tested in the last two world championships, and the results were what the international governing body hoped for: While almost half of the games at the Vancouver Olympics were victories by five goals or more, there were only five such blowouts in the 2012 worlds and four in '13.

NASTY NEIGHBORS: How dominant are the United States and Canada?

They have won all four golds, three silvers in a bronze at the Olympics, and in the world championships no other nation has ever even made the title game. After the Americans won it all at the 1998 Winter Games in Nagano, Canada has won the last three Olympic tournaments, and perhaps that's the reason that a couple of the teams' pre-Sochi exhibitions ended with brawls.

"The passion behind the rivalry is something that fuels our play every day," U.S. captain Megan Bozek said. "We face them so many times over our careers, and it's always an incredible hockey game."

American forward Julie Chu will play in her fourth Olympics. The U.S. team is coached by Harvard's Katey Stone.

THE FINNISH FENCE: In hockey, a goalie on a hot streak can make all the difference. And Finland may have the person who can lead her team to an upset in Sochi.

Noora Raty was only 15 when she was the starting goalie for Finland's national team in Turin in 2006. Four years later in Vancouver, she led her country to the bronze medal.

Raty then returned to the University of Minnesota to finish a college career in which she posted a 1.34 goals-against average, including a 41-0 record and a 0.96 GAA as a senior while winning her second straight NCAA championship. At the Four Nations Cup in November, she made 58 saves to lead Finland to a 3-1 wakeup call over the United States.

"She's one of the best goaltenders in the world. It's hard to score on her," said U.S. defenseman Megan Bozek, Raty's teammate at Minnesota. "But I think it makes it that much sweeter when you do get that goal on her."

CARRYING THE FLAG: Canada has never sent a hockey team to the Olympics without Hayley Wickenheiser.

The 35-year-old forward known as the Wayne Gretzky of women's hockey will be playing her fifth Winter Games and going for her fourth gold medal. (She also played on the Canadian softball team that finished tied for last in the 2000 Summer Games in Sydney.) Wickenheiser was a pioneer in the women's game — the first woman who wasn't a goalie to play full-time in a men's professional league — and she was chosen as Canada's flag-bearer for the Opening Ceremonies.

But Wickenheiser was stripped of her captaincy by new coach Kevin Dineen, who was brought on to coach the team in December after Dan Church's surprise resignation. After beating the Americans three straight times in their pre-Olympic tuneup series before Church stepped down, the United States won the next four.

HOME ICE ADVANTAGE: Despite its tradition as a men's hockey power — and remember, the dominance of what was then the Soviet Union was the reason the Miracle on Ice was such a miracle — the host nation has never made much of a dent in the women's game. Russia won a bronze medal in the 2001 world championships and then didn't return to the podium at worlds for a decade.

But the Russians finished third at last year's worlds, giving the hosts hope that they can reach the medal round at the Olympics for the first time.